The narrative tone in "The Rocking-Horse Winner" is fairly neutral—the narrator presents most of the characters in a straightforward manner, describing events in a no-nonsense manner as they happen. Paul, Oscar Creswell, Basset, and the other minor characters seem relatively normal through the eyes of the narrator, whose attitude towards those characters does not trend particularly positive or negative. The narrator presents Paul as a rather intense young child, but this does not seem to be a character flaw in the narrator's eyes:
The child had never been to a race-meeting before, and his eyes were fire blue. He pursed his mouth tight, and watched.
If anything, Paul's intensity is portrayed by the narrator as part of his childish nature; any problems he facilitates or creates with regards to money are blamed on negative adult influence. This kind of neutral, measured tonal attitude is quite common with omniscient third-person narrators like the one in "The Rocking-Horse Winner."
However, the narrator takes an entirely different tone when discussing Hester. She is portrayed as emotionless, and she's blamed for many subsequent problems. Lawrence begins the story with the narrator describing Hester in a rather unforgiving manner:
She had bonny children, yet she felt that they had been thrust upon her, and she could not love them. They looked at her coldly, as if they were finding fault with her. And, hurriedly, she felt she must cover up some fault in herself.
In this passage, the narrator's tone is somewhat accusatory, seemingly placing the blame entirely on Hester for her children's suffering. Her lack of affection and refusal to be "motherly" lead her children—Paul in particular—down unsavory paths and to their eventual demise. It is no coincidence that Hester is the only main female character in the story. In a time when women were expected to do the bulk of the emotional labor for the household, they were primary targets for blame whenever something bad happened to their children. The narrator's tone thus mirrors the prevailing attitude towards supposedly negligent mothers during the period in which this story was written (the 1920s).